Well I think they should be a very low number of them. But when one think it is required, it should clearly state for which use case it is.
For me, it should be in the form of “Seel also” which links other specific cases.
It is not needed, the discuss web site is automatically in multi-language thanks to the translation tools.
Yes I think all howto’s should be written in English (even if on support part of the forum we accept any language).
For me, only if it was created with Scripting Tryton Tutorial Video and published on our Youtube channel.